“Sometimes people don’t have 25,000 miles for a round trip ticket but they’ve got 12,500,” said MileWise co-founder and co-CEO Sanjay Kothari. “With Combo Fares, you can do one search and see all the different options for both outbound and return flights in one place.”

For example, during a recent search for a flight between Los Angeles and New York, the site returned several dozen results, including a round trip on US Airways for $385 (the lowest cash fare available), a round trip award ticket on Alaska for 25,000 miles and a Combo fare that combined an outbound flight on United for 12,500 miles and return flight on US Air for $137.

Valuing those miles at 1.4 cents per mile, Kothari calculates that the Combo fare essentially cost $315, significantly cheaper than either the Alaska award (valued at $353) or the US Air cash fare.

“There’s a general misconception out there that mileage seats are never available,” he told NBC News, “but our results show that there are always some.”

“The problem is that there’s no transparency with awards,” said Brian Kelly of ThePointsGuy.com. “The Kayaks and Travelocitys of the world have done a decent job of providing it for paid fares, but as far as award tickets go, it’s been a free-for-all.”

MileWise seeks to simplify the process by serving as a metasearch engine for award seats. It will work for any user but is most effective for those who register and provide their specific frequent-flier account details. For the latter, the site will return the most relevant results: i.e., flights based on actual account balances and status.

And in a clever bit of marketing, the site also assigns each flight a “WisePrice,” which calculates the miles or points you earn for cash tickets and “subtracts” it from the retail price. In the above example, the $137 US Air ticket would add 2,464 miles to your account, worth approximately $34.

Alas, you’d still pay the full $137 fare, but to Kothari, at least, “you’re earning $34 worth of ‘currency.'”

The site is not without issues. Since all flights are booked on the airlines’ proprietary sites, Combo Fares require two separate reservations, which can lead to technical difficulties. During the above search, for example, the US Air link connected directly to a page offering a round trip fare of $435, requiring another round of clicks to access the appropriate $137 one-way fare.

The bigger issue — and one that also impacts users of other mileage-tracking sites, such as AwardWallet and Traxo — is that airlines are beginning to take issue with the sites’ accessing their plan members’ data. In recent months, both American and Delta have threatened legal action against the sites, forbidding access to members’ accounts.

“It’s a shame that airlines are using this ruse that it’s a security issue,” said Kelly. “If banks and credit-card companies can link to other third-party apps, there’s no reason the airlines shouldn’t allow consumers to use applications that simplify their lives.”

For his part, Kothari says he’s currently in discussions with American and Delta and “hopeful” that they’ll come to an agreement that will allow MileWise to access members’ accounts and show award availability again.

In the meantime, Kelly suggests that websites like MileWise should be considered, not as the final arbiter of award availability, but as additional tools in your frequent-flier arsenal.

“At the end of the day, these sites can help but they’re not the final answer,” he told NBC News. “The bottom line is to educate yourself about the programs you participate in, know the ins and outs and leverage that information to get the most value out of your miles.”

Rob Lovitt is a longtime travel writer who still believes the journey is as important as the destination. Follow him on Twitter.